This Application claims priority of China Patent Application No. CN 201310313434.2, filed on Jul. 24, 2013, and the entirety of which is incorporated by reference herein.
Field of the Invention
The present disclosure relates to a touch panel technology, and in particular, a touch panel and a test method thereof.
Description of the Related Art
Widely adopted electronic systems such as a Personal Digital Assistant, handheld game console, smart phone, and tablet PC may include a touch panel and a monitor. Because the touch panel may be disposed above the monitor, a touch sense layer in the touch panel could easily be coupled together by the electromagnetic interference from the monitor and consequently, sense precision thereof would be reduced.
In order to enhance interference resistivity for the touch panel, a shielding layer is typically disposed at the touch sense layer on the side of the touch panel, close to the monitor, thereby preventing the touch sense layer from being affected by the electromagnetic interference from the monitor. The shielding layer is connected to a ground of the system via a Flexible Printed Circuit (FPC), to form a leaking path for the shielding layer. The electrical characteristics of the leaking path will impact the shielding performance of the shielding layer. Thus, the leaking path of the shielding layer is tested when tests are conducted on the touch panel.
The current approach for testing the leaking path of the shielding layer involves providing a signal with a fixed frequency by a testing device to the shielding layer, to measure capacitance of the coupling capacitor between the shielding layer and the touch sense layer. If the measured capacitance is different from the default value, it will be determined that the leaking path of the shielding layer has poor electrical characteristics, which may have been, for example, caused by a poor connection between the FPC and the shielding layer.
An alternative current (AC) characteristic of the shielding layer is used for testing of the coupling capacitor. Therefore, when the resistance of the shielding layer is abnormally high and exceeds a defined working range, the test may not efficiently and correctly identify problems which may be occurring. Subsequently, the shielding layer may not perform normally. As a result, the interference resistivity of the shielding layer will be reduced.